Currently, mobile communication of the second generation mobile communications technology (The second generation, 2G), the third generation mobile communications technology (The 3rd Generation, 3G), and the fourth generation mobile communications technology (The 4th generation, 4G) develops jointly, and many operators operate networks in multiple modes at the same time, for example, operate a Global System for Mobile communications (Global System of Mobile communication, GSM)/Universal Mobile Telecommunications System (Universal Mobile Telecommunications System, UMTS) dual-mode network, that is, a 2G/3G network. As this type of network emerges, growing demands for mobile services can be satisfied on one hand, and sharing of a multi-standard site can be implemented on the other hand, which facilitates smooth evolution of a 2G network to a 3G network. With accelerated development of 4G mobile broadband, in the future, a 2G/4G or 3G/4G single radio access network (Single Radio Access Network, SRAN) network will also emerge, and on the basis of constantly satisfying rapidly growing demands for mobile broadband services, smooth evolution to a 4G network will be implemented.
However, in an existing dual-mode or multimode network, a base station cannot flexibly control transmit power according to a need of a user in a coverage cell, which results in a low overall energy efficiency of a network in which the base station is located.